Enable Monitor and Cosmics chains (ATR-28359, ATR-28357)

Once !66702 (merged) is merged, we can enable both the Monitor and Cosmics signatures. They no longer cause python crashes.

Note that there are still many unmigrated chains that fail menu generation but only give a warning:

Py:TriggerMenuMT:ChainConfigurationBase WARNING CA migration: [getStep] Menu sequence precisionTrackingSequenceCfg does not exist for CA components 
Py:TriggerMenuMT:ChainConfigurationBase WARNING CA migration: [getStep] Menu sequence precisionTrack_GSFRefittedSequenceCfg does not exist for CA components 
Py:TriggerMenuMT:GenerateMenuMT WARNING CA migration: [__generateChainConfigs] chain HLT_e140_dnnloose_L1eEM28M generation missed configuration

Trigger/TriggerCommon/TriggerJobOpts/python/runHLT.py

@@ -63,7 +63,7 @@ def set_flags(flags):
    # FIXME: disable coherent prescales during development phase to allow menu with single-chain CPS groups
    flags.Trigger.disableCPS = True
    #These signatures cause a Python crash - wait for CA migration
-   flags.Trigger.disabledSignatures = ["UnconventionalTracking", "Monitor", "Cosmics"]
+   flags.Trigger.disabledSignatures = ["UnconventionalTracking"]
 
 
 def runHLTCfg(flags):